ABSTRACT
Nanofibrous filter materials were prepared by electrospinning a solution of 28 wt% poly(vinylidene fluoride) in N,N-dimethylacetamide with and without the addition of 2 wt% AgNO3, Cu(NO3)2·2.5H2O or ZnCl2. X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy, inductively coupled plasma mass spectroscopy, thermogravimetric analysis, contact angle measurement, nitrogen sorption, and mercury intrusion porosimetry methods were used for the characterization of physical structure as well as the chemical composition of the electrospun materials. Particle filtration efficiency and antiviral activity against the SARS-CoV-2 alpha variant were tested in order to estimate the suitability of the prepared electrospun filter materials for application as indoor air filtration systems with virucidal properties. All filter materials prepared with salts demonstrated very high particle filtration efficiency (≥98.0%). The best antiviral activity was demonstrated by a material containing Cu(NO3)2·2.5H2O in the spinning solution, which displayed the decrease in the number of infectious virions by three orders of magnitude after a contact time of 12 h. Materials with the addition of AgNO3 and ZnCl2 decreased the number of infectious virions after the same contact time by only â¼8 and â¼11 times, respectively.
ABSTRACT
Nanowire poly(vinylidene fluoride) (PVDF) polymer membranes activated with Ag and Zn nanoclusters were prepared using the electrospinning method. The structure of membranes was varied by using different polymer concentrations in N,N-dimethylacetamide, electric field strength, and concentration of AgNO3 and ZnCl2 in an electrospinning solution. Materials synthesised were analysed by nitrogen sorption and mercury intrusion porosimetry, X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectroscopy, thermogravimetry, inductively coupled plasma mass spectroscopy, particle filtration efficiency, and pressure drop methods. The concentration of Ag and Zn nanoclusters in PVDF membranes was established and the influence on nanofibers activity has been discussed. The hydrophobicity of membranes was tested using the wetting (contact) angle measurement method. The human influenza A virus (IAV) A/WSN/1933 (H1N1) strain was used to evaluate the virucidal activity of filtration materials. The virucidal activity increased with Ag nanoclusters concentration in fibres. The most hydrophilic nanofibers with Zn nanoclusters showed very high and practically concentration independent virucidal activity that was two orders of magnitude higher compared to materials activated with Ag nanoclusters.